Stable Germylenes Derived from 1,2-Bis(arylimino)acenaphthenes

Metal exchange reactions of the magnesium complexes (dpp-BIAN)Mg(THF)n, (dtb-BIAN)Mg(THF)n, and (bph-BIAN)Mg(THF)n with GeCl2(dioxane) afford the stable germylenes (dpp-BIAN)Ge (1), (dtb-BIAN)Ge(Et2O) (2), and (bph-BIAN)Ge (3), respectively (dpp-BIAN = 1,2-[(2,6-iPr2C6H3)N]2C12H6, dtb-BIAN = 1,2-[(2,5-tBu2C6H3)N]2C12H6, bph-BIAN = 1,2-[(2-PhC6H4)N]2C12H6). Compound 1 is also obtained from (dpp-BIAN)Na4 and GeCl4 in Et2O.
The germylenes 1−3 were characterized by elemental analyses, 1H NMR, 13C NMR, and IR
spectroscopy, and X-ray crystal structure analyses. In the monomeric molecules the two
imino nitrogen atoms coordinate the germanium atom. The aryl(N) groups are arranged
rather orthogonal to the acenaphthenediimine plane. Compound 3 shows an anti geometry
with the ortho phenyl substituents of both N-phenyl rings positioned on opposite sides of
the acenaphthenediimine plane. The bite angles N−Ge−N are 85.2° (1) and 85.0° (3),
respectively. The Ge−N bond distances in 1−3 range from 1.878 to 1.915 Å.